Piotr Marcin Gacek (born 16 September 1978) is a former Polish volleyball player, member of the Poland men's national volleyball team in 2005–2010 and 2015–2016, 2009 European Champion, silver medallist of the 2006 World Championship, two–time Polish Champion (2009, 2010).

[1] His first professional club was SKS Mechanik Nysa and then he played for PGE Skra Bełchatów.

On April 19, 2015 LOTOS Trefl Gdańsk, including Gacek, achieved the Polish Cup 2015.

[6] Gacek ended up sporting career on April 13, 2017 after last match of the 2016–17 PlusLiga at Ergo Arena.

On August 26, 2017, before the match Poland – Finland at the 2017 European Championship in Ergo Arena, Gdańsk, was held a brief ceremony to thank him for career in national team.